#include <STC15F2K60S2.H>
#include <intrins.H>

sbit TX = P1^0;
sbit RX = P1^1;


void Delay13us()		//@12.000MHz
{
	unsigned char i;

	_nop_();
	_nop_();
	i = 36;
	while (--i);
}




void ultra_int()
{
	uchar i;
	for(i=0;i<8;i++)
	{
	TX = 1;
	Delay13us();
	TX = 0;	
	Delay13us();
	}
}



uchar ultra_read()
{

	uint temp;
	CH = CL = 0;
	CMOD = 0;
	EA = 0;
	ultra_int();
	EA = 1;
	CR = 1;
	while((RX ==1) && (CF == 0));
	CR = 0;
	if(CF  == 0)
	{
		temp = (CH<<8)|CL;
		return temp*0.017;
	}else{CF = 0;return 0;}








}